When thinking about mangroves, some of us might imagine a messy tangle of roots sticking out of murky waters infested with eerie creatures. Walking through them is often portrayed as dangerous in movies, on par with wading dark swamps or trekking lost jungles. While mangroves are indeed mysterious, these unique ecosystems are in fact more magical than we’d ever expect.

Their wondrous benefits have attracted a significant amount of attention, starring in shows like Our Planet and Seaspiracy. Much of the reason why our magnifying lens has recently focused on mangroves is the drastic loss of these ecosystems around the globe over the past forty years, and the persisting threats to their ecological, economic and societal value.

Mangrove forests are among one of the most productive ecosystems on Earth, growing on the interface between land and sea in most of the world’s tropical coastlines. They exist in extreme conditions, with high salinity, extreme tides, high temperatures and strong winds. Representing the only group of trees in the world that can survive in salt water, mangroves provide a set of unique ecosystem services.

One of the most intrinsic values of mangroves is their rich biodiversity. They are breeding grounds for many of the world’s sea life, and they support thousands of marine and terrestrial species from barnacles to macaque monkeys. Mangroves are also home to many endangered species of animals such as the dugong, found in East Africa and Australia, and the Bengal tiger, which lives in the mangroves of India’s Sundarbans region. In the remote Isla Escudo de Veraguas off the coast of Panama, mangroves are inhabited by the critically endangered pygmy three-toed sloth, of which only 500 individuals are left. Many other animals choose to call mangroves their home – the proboscis monkey, smooth-coated otters, olive Ridley turtles, manatees… What a wonderful plethora of residents!

Often, mangroves coexist with seagrass meadows, salt marshes and coral reefs, collectively termed ‘blue forests’. In many places, mangroves are the first line of defence against pollutants and sediments which would otherwise flow out into the sea and harm the seagrass beds or the reefs. Not only that, but mangroves have been shown to protect corals from mass bleaching events. In a study in the Virgin Islands, more than 30 species of corals were found amongst the roots of mangrove trees, surviving bleaching that devastated the nearby reef. Mangrove trees also regulate water flowing from the sea, regulating the salinity and preventing saltwater from encroaching into inland waterways.

The complex, sturdy root system of mangroves is not just a defence from pollutants, but it can act as a preventive measure against storms, extreme tides and even tsunamis. With about 2.4 billion people living within 100 km of the coast according to the UN, mangroves can make a substantial difference to the safety of many communities. When the 2004 tsunami hit Tamil Nadu, India, the trees standing in the front lines were damaged, but the mangrove forest behind absorbed the shock protecting over 1,700 people living within 1,000m from the shore. Similarly, the presence of mangroves in Florida reduced the impacts caused by Hurricane Irma in 2017 by 25%, protecting half a million people and preventing US $1.5 billion in direct flood damages.

As the risk of severe weather events increases with climate change, protecting mangroves becomes even more crucial. Although they only make up 0.1% of all tropical forests, mangroves store the most carbon in the tropics, absorbing up to four times the amount of carbon dioxide (CO2) than upland terrestrial forests. This is because of the unique decomposition cycle of these ecosystems. When the leaves, branches and roots of mangroves die, they are immediately covered by soil and submerged under tidal water. This slows down the decay of organic material, trapping huge amounts of CO2. According to researchers at Harvard University, mangroves stored 4.19 Pg (petagram) of carbon in 2012 alone, 50% of which was shared between Indonesia, Brazil, Malaysia and Papua New Guinea. If one petagram is equal to one billion metric tons, which is equivalent to a train measuring 156,500 miles carrying 100 tons of coal (which contains 80% carbon) on each freight-car, this means that mangroves can store more than 4 times that amount. Mangroves are true carbon superstores.

On top of protecting people from tsunamis and climate change, mangroves play an essential role in providing food, shelter and livelihoods for local communities. As UNEP-WCMC state, mangroves are vital for millions of people who rely on the seafood, construction timber, fuel, medicinal plants provided by these forests. In fact, mangroves are so important to people’s livelihoods that they play a pivotal part in the UN’s sustainable development goals of poverty reduction, food security, gender equality and clean water and sanitation.

Despite being so crucial under so many aspects, about 35% of mangroves were lost between 1980-2000 according to the IUCN, and a further 20% between 2000-2012. Not only does this cause losses in biodiversity, livelihoods and tidal protection, but it also creates hotspots of carbon dioxide emissions in major mangrove-rich regions. According to a study led by Griffith University in Australia, much of the future CO2 emissions will be caused by mangrove clearance and the associated erosion in southeast and south Asia, the Caribbean, west Myanmar and north Brazil. Most of the threats arise from the clearance of mangroves and conversion of land for agriculture and aquaculture. According to the WWF, shrimp farming has had some devastating effects on mangroves around the world, and the controversial documentary Seaspiracy has suggested that this industry has caused the destruction of over 38% of mangroves. Stewardship councils in the fishing sector such as the ASC have responded by stating that not all shrimp farms destroy mangroves and that many farmers run their practice in a responsible way. While they might only be trying to protect their image, the ASC points out that it’s not just shrimp farms that harm the mangroves – it’s also the coastal development sector, which is often unregulated. Indeed, rapid urbanisation and the establishment of factories, roads and harbours are potentially the greatest immediate threat to mangroves in the Caribbean. In Abu Dhabi, the highly engineered shoreline and development of cement factories near the mangroves leads to deposition of heavy metals and other particulates. In the Wouri mangrove forests of Cameroon, recent population growth has put these ecosystems under intense stress caused by plastic pollution, which not only affects flora and fauna by directly congesting the forests, but also leads to the release of microplastics which become absorbed by organisms on all levels of the food chain.

Nevertheless, the environmental and economic benefits of mangroves are no longer going unnoticed. The increasing rise in awareness about mangroves, perpetuated by activists, documentaries and the scientific community, has led to many protection and restoration initiatives. Projects like Save Our Mangroves Now!, led by BMZ (German Federal Ministry for Economic Cooperation and Development), IUCN and WWF, are encouraging global efforts on a governmental level to stop the degradation of mangroves around the world. Other partnerships like the Mangrove Alliance are building collaborations with local communities, scientists and conservation organisations. Some success stories are finally arising from this worldwide rise in awareness. In Thailand, the destruction of much of the coastline following the 2004 tsunami sparked an effort to recover mangrove forests by replanting the trees. While the intensive shrimp farming had previously caused land degradation and disease outbreaks among shrimp batches, initiatives for sustainable shrimp farming have resulted in improved environmental and social integrity. Similarly in Vietnam, one of the countries expected to be worst hit by climate and sea level change, mangrove restoration programmes have been implemented in the Cape Ca Mau National Park. Here, a mixed approach involving replanting and sustainable shrimp farming have improved both people’s livelihoods and biodiversity.

As we enter the UN’s Decade of Ecosystem Restoration (2021-2030), mangroves must become a major focus of our conservation and restoration projects. With their ability to support complex and rich ecosystems, protect endangered species, and provide livelihoods for the millions, mangroves are no longer something we can overlook. Conserving and restoring them could be a solution to many of our problems, and get us closer to conquering our fight against climate change.

Dael Sassoon

Dael Sassoon is a PhD candidate in Physical Geography at the University of Manchester, studying peatlands in the Peruvian Amazon. When he isn’t working on his research, Dael enjoys nothing more than a walk in the woods and writing about his travels. Through his photography and writing, he hopes to channel his passion about the natural world to other wanderlust souls.

You can find out more about him on his website intotheforestblog.weebly.com, or follow him on Instagram @dael_sassoon.

Why We Can't Afford to Lose Mangrove Ecosystems

Dael Sassoon